Baud rate modulation encoding/decoding method and device for remote controller

ABSTRACT

The present invention generally relates to encoding/decoding method and device used for remote controller, which utilizes baud rate to encrypt data for transmission. The encoding device of the present invention comprises an encoder for encoding an identification code into an encrypted code; an interpreter for interpreting the un-encoded portion of the identification code and the encrypted code into a transmission signal. Wherein, when the encrypted code is in a first base, the plain code corresponding to the encrypted code will be transmitted with a first baud rate; and when the encrypted code is in a second base, the plain code corresponding to the encrypted code will be transmitted with a second baud rate. The decoding device according to the present invention comprises a receiver for receiving the transmission signal; a interpreter connected to the receiver for interpreting the transmission signal into a received signal; a encoder for utilizing the same encoding algorithm as in the transmitter to generate a comparison code; and a processor for comparing the received signal and the comparison code and for the process control.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to wireless signal transmissionencoding/decoding method and device, more particularly, toencoding/decoding method and device that utilizing baud rate to encryptdata for transmission.

2. Description of the Prior Art

Remote controller is used wildly in our daily life. Its application canbe found in many fields such as car security, house security,audio/video equipment, and other appliances. In such applications,remote controller plays an important roll in convenience for usage.Although in many applications, security is not a major concern, it is acritical issue in some certain circumstances such as in car securitysystem, home security, and TV channel protection.

In general, the remote controller system can be classified into twocategories of one-direction and bi-direction. In a one-direction remotecontroller system, transmitter simply transmits control signal tocontrol equipment in remote location. While in a bi-direction remotecontroller system, control signal is transmitted interactively betweentransmitter and receiver. The bi-direction remote controller system ismuch more reliable for it employs the function of mutual authentication.However, since it is complex and expensive, it is seldom used except insome certain cases.

In a simplest remote controller system, the control signal is formattedin plaintext and transmitted wirelessly to the receiver. Since thecontrol signal is transmitted in plaintext, it is so easy to beeavesdropped and modified by a hacker, so the system is extremelyunsecured. A common example can be seen pretty often in daily life, thatis, when someone uses a remote controller for opening his own garagedoor, he is opening his neighborhood's garage door at the same time.

As technology advanced and for security reason, more and more remotecontrollers transmit signal in encrypted format, which means, when aremote controller is transmitting signals, the signal is separated intoplain code and encrypted code. The plain code is in regular format,comprising fixed data structure, while the encrypted code, intransmission, is encrypted with certain mathematical algorithm and isdifficult to be decoded by hacker. The concept of encrypting signal forsecurity reason is not so difficult to understand, however, thepractical implementation is quite complex, and the cost is relativelyhigh. The present invention is to disclose a signal transmitting methodand device that plain code and encrypted code will be encapsulated inone single signal. The application can be seen where the plain code isused in a public entrance security system such as a community gateway ora public garage door that only need the plain code for identification,while in different application such as a private garage door securitysystem, the plain code and the encrypted code will be verified in thesame time for strict authentication.

SUMMARY OF THE INVENTION

Accordingly, it is the primary object of the present invention toprovide wireless signal transmission encoding/decoding method anddevice, more particularly, the encoding/decoding method and device thatutilizes logical algorithm to encrypt signal for transmission.

It is the second object of the present invention to encoding/decodingmethod and device that is simple and less expensive.

The method of the present invention is to employ baud rate modulation toencrypt transmission data and encapsulate the transmission data intransmission signal for transmission, comprising the steps as follows:

(a). utilizing a identification signal to generate a plain code and aencrypted code;

(b). utilizing the encrypted code to control the baud rate fortransmitting the plain code; when the encrypted code is in a first base,the plain code corresponding to the encrypted code will be transmittedwith a first baud rate; when the encrypted code is in a second base, theplain code corresponding to the encrypted code will be transmitted witha second baud rate.

The device of the present invention is to employ baud rate modulation toencrypt transmission data, comprising:

an encoder for receiving an identification code and encoding a portionof the identification code into an encrypted code;

an interpreter being connected to the encoder for complying theun-encoded portion of the identification code and the encrypted codeinto a transmission signal;

wherein, in the encoding process, the encoder will encode the length ofthe waveform of the un-encoded portion of the identification codeaccording to the following rules,

(1). when the encrypted code is in a first base, the plain codecorresponding to the encrypted code will be transmitted with a firstbaud rate;

(2). when the encrypted code is in a second base, the plain codecorresponding to the encrypted code will be transmitted with a secondbaud rate.

The decoding device of the remote controller of the present inventioncomprises:

a receiver for receiving transmission signal;

an interpreter being connected to the receiver for utilizing a givenbaud rate to interpret the transmission signal into a received signal;

an encoder utilizing a logical algorithm to generate a comparison code;and

a processor being connected to the interpreter and the encoder forcomparing the received signal and the comparison code to determine ifreceive the instruction carrying on the transmission signal andcontrolling the process.

Other and further features, advantages and benefits of the inventionwill become apparent in the following description taken in conjunctionwith the following drawings. It is to be understood that the foregoinggeneral description and following detailed description are exemplary andexplanatory but are not to be restrictive of the invention. Theaccompanying drawings are incorporated in and constitute a part of thisapplication and, together with the description, serve to explain theprinciples of the invention in general terms. Like numerals refer tolike parts throughout the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects, spirits and advantages of the preferred embodiments of thepresent invention will be readily understood by the accompanyingdrawings and detailed descriptions, wherein:

FIG. 1 is a schematic block diagram showing a transmitter according tothe present invention.

FIG. 2 is a schematic block diagram showing an identification signalaccording to the present invention.

FIG. 3 is a flow chart showing the encoding process according to thepresent invention.

FIGS. 4A & 4B are diagrams showing the complied signal according to thepresent invention.

FIG. 5 is a flow chart showing the encoding process in a transmitteraccording to the present invention.

FIG. 6 is a schematic block diagram showing a receiver according to thepresent invention.

FIG. 7 is a flow chart showing the decoding process in a transmitteraccording to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention providing wireless signal transmissionencoding/decoding method and device utilizing logical algorithm toencrypt data for transmission can be exemplified by the preferredembodiments as described hereinafter.

Please refer to FIG. 1, which is a schematic block diagram showing atransmitter according to the present invention. As shown, anidentification signal 10 is input into an encoder 15 and an interpreter16 in sequence. Then, please refer to FIG. 2, which is showing anidentification signal according to the present invention. As shown inFIG. 2, the identification signal 10 contains three sections. The firstone is a vendor code 100, which is an 8-bits code and represents thevendor business identification code. The second one is a user group code101, which is a 16-bits code and is designated for the user having sameproperty, such as working in the same company, same department or livingin the same residential area. The third section is a user code 102,which is a 16-bits code and is used for a single user uniquely. In theembodiment of the present invention, the vendor code 100 and the usergroup code 101 consist of a plain code 11, and the user code 102 isencoded and hidden in the plain code 11. The user code 102 in theidentification signal is retrieved from the encoder 15 and encoded to bean encrypted code 150, and then transmitted to the interpreter 16. Theinterpreter 16 complies the vendor code 100 and the user code 102 in theidentification signal 10 into plain code and converts the encrypted code150 with baud rate modulation, and then complies these three codes intoa transmission signal 18. The present invention provides two layers ofprotection, that is, the signal is first interpreted by the interpreter15 and then modulated with baud rate, whereby the protection for theidentification signal is therefore enhanced.

FIG. 3 is a flow chart showing the encoding process according to thepresent invention. As seen, the user code 102 in the interpreter 15 isused for generating an encrypted code 150 that is generated by anencrypted code generator 151. The encrypted code generator 151 not onlyre-encodes the user code 102 with mathematical algorithm but alsonormalizes the length of the encrypted code 150. After being normalized,the length of the encrypted code 150 is same as that of the plain code11. The normalization can be performed before or after the encodingprocess, or even during the process. In present embodiment, the lengthof the plain code 11 is consistent of the 8-bits vendor code 100 and16-bits user group code 101, that is, the total length of the plain code11 is 24 bits. However, the length of the user code 102 is 16-bits sothat it has to be adjusted to 24-bits to match the length of the plaincode to meet the requirement for the interpreter 16. In the embodimentof the present invention, the normalization is completed before theprocess performed by the encrypted code generator 151. Each length ofthe high byte 1020 and the low byte 1021 of the user code 102 is 8 bits,and a 24-bits temporary code 1520 is obtained after normalization. Thereare many ways can be used to achieve the normalization. In the presentinvention, the Exclusive OR (XOR) operation applying on the high byte1020 and the low byte 1021 of the user code is employed to obtain threebytes, the first byte to the third byte, and said three bytes arefurther consolidated to be the temporary code 1520.

Following the process of obtaining the temporary code 1520, as shown, isthe process for generating the encrypted code 150. They are manytechniques, such as multinomial method or the famous one as RSA, can be1o used to provide the encryption function in the encrypted codegenerator 151. In the present invention, the Exclusive OR (XOR)operation 1520 is adapted to apply on the previous encrypted code 150 toobtain a new encrypted code. The advantages of Exclusive OR (XOR)operation include less complexity and low cost, and one solution can beused for both encoding and decoding. Here rises a problem when firsttime initiate the encrypting process, that is, how to obtain the“previous” encrypted code to generate a new encrypted code? Apre-determined value is the solution of the problem. A pre-determinedvalue can be treated as the “previous” encrypted code for generating anew encrypted code. The major reason for using the previous encryptedcode to generate a new encrypted code is to prevent the “replay attack”submitted by a hacker. The function of the controller 153 is to convertthe reset signal 154 into an encrypted code 150 and transmit it to theinterpreter 16 or directly transmit the encrypted code 150 that isgenerated by the encrypted code generator 151 to the interpreter 16. Thereset signal 154 can be set up in advance, and in this embodiment, thereset signal is defined as EF-FF-FEH.

Referring back to FIG. 1, the interpreter receives the encrypted code150 generated by the encoder 15 and converts it with the plain code 11in the identification signal 10 into the transmission signal 18. Therules for generating the transmission signal 18 include: first, theheight of the waveform of the plain code 11 is lept unchanged, second,the length thereof is changed according to the following rules,

(1). when the encrypted code 150 is in a first base, the plain codecorresponding to the encrypted code 150 is transmitted with a first baudrate;

(2). when the encrypted code 150 is in a second base, the plain codecorresponding to the encrypted code 150 is transmitted with a secondbaud rate.

For example, when the encrypted code 150 is 0, the baud rate fortransmitting the plain code 11 is unchanged; when the encrypted code 150is 1, the baud rate will be reduced to half and the length of waveformis extended to two times long. Please refer to FIG. 4A & 4B, which arediagrams showing the complied signal according to the present invention.In the present embodiment, 3 bits are used to represent 0 or 1, that is,it represents 0 when these 3 bits are in 100, and 1 when 110. This willreduce the identification error occurred in the receiver 7, and only onetime voltage change will occur in each bit, which make it easier for thereceiver 7 to measure the length of bits. The present embodiment alsoillustrates that the baud rate is not changed when the encrypted code150 is 0, which means there is no operation executed in the interpreter16, and that baud rate of the plain code 11 will be reduced to half;meaning the length of the waveform is extended to two times long, by theinterpreter 16 when the encrypted code 150 is 1. As shown in FIG. 4A,which is showing the waveform When the plain code 11 is in the format of0011010, it is also the same waveform when the encrypted code 150 is inthe format of 000000. As seen in FIG. 4A, the waveform of the 2, 4, 6and 7 bit of the plain code 11 are needed to be extended to two timeslong when the encrypted code 150 is in the format of 0101011.

Please refer to FIG. 5, which is a flow chart showing the encodingprocess in a transmitter 1 according to the present invention. As seen,it comprises the following steps,

Step 51. generating the identification signal 10;

Step 52. checking if it is a reset signal 154, executing step 56 whenyes, executing step 53 when no;

Step 53. executing the encoding process on the identification signal 10to obtain an encrypted code 150;

Step 54. checking if the encrypted code 150 is equal to thepre-determined value that is representing the reset signal 154,executing step 5 when yes, executing step 55 when no;

Step 55. combining the encrypted code 150 and the plain code 11,complying them into the transmission signal 18 and transmitting thesignal;

Step 56. setting up the encrypted code 150 to be the pre-determinedvalue that is representing the reset signal 154 and executing the step55.

FIG. 6 is a schematic block diagram showing a receiver according to thepresent invention. As shown, the receiver end 6 receives thetransmission signal 18 and converts it back to identification signal 10for user identification and executing instructions. As seen, thereceiver end 6 comprises a receiver 61, an interpreter 63, an encoder 65and a processor 67. The receiver 61 is for receiving the transmissionsignal 18. The interpreter 63 is connected to the receiver 61 and willinterpret the transmission signal to a received signal 68. The encoder65 employs the same rules as in the encoder 15 of the transmitter 1 togenerate a comparison code 60. The processor 67 is connected to theinterpreter 63 and the encoder 65, and will compare the received signal68 generated by the interpreter 63 with the comparison code 60 generatedby the encoder 65. The process will be executed when the received signal68 is totally matched to the comparison code 60. If not matched, itcould be the situation that a hacker is trying to start a attack, or thesituation that a legal user hits the emitting switch by mistake to causethe encrypted code 150 in the transmitter end 1 exceed the process, so,in that case, even a legal user will not be able to start the process.In order to solve the above problem, an error allowance number 66 can beset up in advance. So, when the match is not correct, the receiver endwill automatically move to next comparison code 60 and compare it againwith the received signal 68. If matched, the process will continue, ifnot, the process will move again to the next comparisons code 60 and dothe comparison until the number equal to the error allowance number 66.Here comes a problem, if the legal user makes the mistake for so manytimes, or the receiver end 6 is under the attack from a hacker, thecomparison code will exceed the legal user's encrypted code 150. Thesolution is to use the reset signal 154 to bring the encrypted code 150in the transmitter end 1 and the comparison code 60 in the receiver end6 back to their initial stage, so both of them can be synchronized andthe process will function normally.

FIG. 7 is a flow chart showing the decoding process in a receiver endaccording to the present invention. It comprises the following steps,

Step 70. receiving the transmission signal 18, interpreting it intoreceived signal 68 and executing the step 71;

Step 71. checking if the received signal 68 is the pre-determined valuerepresenting the reset signal 154, executing step 72 when yes, executingstep 74 when no;

Step 72. receiving the next transmission signal 18 and executing thestep 73;

Step 73. storing the encrypted code 150, measuring the next comparisoncode 60 and executing the step 70;

Step 74. checking if the received code 68 is equal to the comparisoncode 60, executing the step 75 when yes, executing the step 77 when no;

Step 75. executing the operation the transmission signal 18 representingfor and executing the step 76;

Step 76. ending and the number of error are 0;

Step 77. measuring the next comparison code 60, adding the number oferror by 1 and executing the step 78;

Step 78. checking if the number of error is equal to the error allowablenumber 66, executing step 76 when yes, executing step 79 when no;

Step 79. checking if the received code 68 is equal to the comparisoncode 60, executing the step 75 when yes, executing the step 77 when no.

Although this invention has been disclosed and illustrated withreference to particular embodiments thereof, and in terms of theillustrative drawings, it should not be considered as limited thereby.Various possible modifications, omission, and alterations could beconceived of by one skilled in the art to form and the content of anyparticular embodiment, without departing from the scope of the presentinvention.

1-13. (canceled)
 14. a decoding device for remote controller thatutilizes baud rate modulation to encrypt transmission signal,comprising: a receiver for receiving a transmission signal; aninterpreter connected to the receiver for utilizing a given baud rate tointerpret the transmission signal into a received signal; an encoderutilizing a logical algorithm to generate a comparison code; and aprocessor connected to the interpreter and the encoder for comparing thereceived signal and the comparison codes to determine if receive theinstruction carrying on the transmission signal and controlling theprocess.
 15. the device of claim 14, wherein the method used forencoding in the encoder is same as the method used for encoding forgenerating the transmission signal.
 16. The device of claim 14, whereinthe processor has a error allowance mechanism which automaticallycorrect the unsymmetrical problem of the comparison code caused by theuser's triggering of the emitting switch by mistake.
 17. The device ofclaim 16, wherein if the asymmetry is beyond the range that can becorrected by the err allowance mechanism, the device can receive a resetsignal to enforce the symmetry of the comparison code.
 18. A decodingdevice for remote controller that utilizes baud rate modulation toencrypt transmission signal, comprising: a receiver for receiving atransmission signal; an encoder utilizing a logical algorithm togenerate a comparison code; an interpreter connected to the encoder forutilizing a given baud rate to interpret the transmission signal into acomparison signal; and a processor connected to the interpreter and theencoder for comparing the received signal and the comparison codes todetermine whether receive the instruction carrying on the transmissionsignal and controlling the process.
 19. The device of claim 18, whereinthe method used for encoding in the encoder is same as the method usedfor encoding for generating the transmission signal.
 20. The device ofclaim 18, wherein the processor has a error allowance mechanism whichautomatically correct the unsymmetrical problem of the comparison codecaused by the user's triggering of the emitting switch by mistake. 21.The device of claim 20, wherein if the asymmetry is beyond the rangethat can be corrected by the error allowance mechanism, the device canreceive a reset signal to enforce the symmetry of the comparison code.